impr: Handle provider opening more centrally, switch to existing provider if same file is being opened again

(cherry picked from commit 89004574d3)

lib/libimhex/include/hex/api/events/events_provider.hpp

@@ -15,7 +15,7 @@ namespace hex {
      * This event is responsible for (optionally) initializing the provider and calling EventProviderOpened
      * (although the event can also be called manually without problem)
      */
-    EVENT_DEF(EventProviderCreated, prv::Provider *);
+    EVENT_DEF(EventProviderCreated, std::shared_ptr<prv::Provider>);
 
     /**
      * @brief Called as a continuation of EventProviderCreated

lib/libimhex/include/hex/api/events/requests_provider.hpp

@@ -10,6 +10,11 @@ namespace hex {
     */
     EVENT_DEF(RequestCreateProvider, std::string, bool, bool, std::shared_ptr<hex::prv::Provider> *);
 
+    /**
+     * @brief Used internally when opening a provider through the API
+    */
+    EVENT_DEF(RequestOpenProvider, std::shared_ptr<prv::Provider>);
+
     /**
      * @brief Move the data from all PerProvider instances from one provider to another
      *

lib/libimhex/include/hex/api/imhex_api/provider.hpp

@@ -117,6 +117,12 @@ EXPORT_MODULE namespace hex {
             bool select = true
         );
 
+        /**
+         * @brief Opens a provider, making its data available to ImHex and handling any error that may occur
+         * @param provider The provider to open
+         */
+        void openProvider(std::shared_ptr<prv::Provider> provider);
+
     }
 
 }

lib/libimhex/include/hex/providers/cached_provider.hpp

@@ -21,7 +21,7 @@ namespace hex::prv {
         CachedProvider(size_t cacheBlockSize = 4096, size_t maxBlocks = 1024);
         ~CachedProvider() override;
 
-        bool open() override;
+        OpenResult open() override;
         void close() override;
 
         void readRaw(u64 offset, void *buffer, size_t size) override;

lib/libimhex/include/hex/providers/memory_provider.hpp

@@ -27,7 +27,7 @@ namespace hex::prv {
         [[nodiscard]] bool isSavable()          const override { return m_name.empty(); }
         [[nodiscard]] bool isSavableAsRecent()  const override { return false;          }
 
-        [[nodiscard]] bool open() override;
+        [[nodiscard]] OpenResult open() override;
         void close() override { }
 
         void readRaw(u64 offset, void *buffer, size_t size) override;

lib/libimhex/include/hex/providers/provider.hpp

@@ -79,6 +79,65 @@ namespace hex::prv {
     public:
         constexpr static u64 MaxPageSize = 0xFFFF'FFFF'FFFF'FFFF;
 
+        class OpenResult {
+        public:
+            OpenResult() : m_result(std::monostate{}) {}
+
+            [[nodiscard]] static OpenResult failure(std::string errorMessage) {
+                OpenResult result;
+                result.m_result = std::move(errorMessage);
+                return result;
+            }
+
+            [[nodiscard]] static OpenResult warning(std::string warningMessage) {
+                OpenResult result;
+                result.m_result = std::move(warningMessage);
+                result.m_warning = true;
+                return result;
+            }
+
+            [[nodiscard]] static OpenResult redirect(Provider *provider) {
+                OpenResult result;
+                result.m_result = provider;
+                return result;
+            }
+
+            [[nodiscard]] bool isSuccess() const {
+                return std::holds_alternative<std::monostate>(m_result);
+            }
+
+            [[nodiscard]] bool isFailure() const {
+                return std::holds_alternative<std::string>(m_result) && !m_warning;
+            }
+
+            [[nodiscard]] bool isWarning() const {
+                return std::holds_alternative<std::string>(m_result) && m_warning;
+            }
+
+            [[nodiscard]] bool isRedirecting() const {
+                return std::holds_alternative<Provider*>(m_result);
+            }
+
+            [[nodiscard]] Provider* getRedirectProvider() const {
+                if (std::holds_alternative<Provider*>(m_result)) {
+                    return std::get<Provider*>(m_result);
+                }
+                return nullptr;
+            }
+
+            [[nodiscard]] std::string_view getErrorMessage() const {
+                if (std::holds_alternative<std::string>(m_result)) {
+                    return std::get<std::string>(m_result);
+                }
+
+                return "";
+            }
+
+        private:
+            std::variant<std::monostate, std::string, Provider*> m_result;
+            bool m_warning = false;
+        };
+
         Provider();
         virtual ~Provider();
         Provider(const Provider&) = delete;
@@ -94,7 +153,7 @@ namespace hex::prv {
          * @note This is not related to the EventProviderOpened event
          * @return true if the provider was opened successfully, else false
          */
-        [[nodiscard]] virtual bool open() = 0;
+        [[nodiscard]] virtual OpenResult open() = 0;
 
         /**
          * @brief Closes this provider
@@ -262,9 +321,6 @@ namespace hex::prv {
         void skipLoadInterface() { m_skipLoadInterface = true; }
         [[nodiscard]] bool shouldSkipLoadInterface() const { return m_skipLoadInterface; }
 
-        void setErrorMessage(const std::string &errorMessage) { m_errorMessage = errorMessage; }
-        [[nodiscard]] const std::string& getErrorMessage() const { return m_errorMessage; }
-
         template<std::derived_from<undo::Operation> T>
         bool addUndoableOperation(auto && ... args) {
             return m_undoRedoStack.add<T>(std::forward<decltype(args)...>(args)...);
@@ -296,8 +352,6 @@ namespace hex::prv {
          */
         bool m_skipLoadInterface = false;
 
-        std::string m_errorMessage = "Unspecified error";
-
         u64 m_pageSize = MaxPageSize;
     };
 

lib/libimhex/source/api/imhex_api.cpp

@@ -391,7 +391,7 @@ namespace hex {
             if (skipLoadInterface)
                 provider->skipLoadInterface();
 
-            EventProviderCreated::post(provider.get());
+            EventProviderCreated::post(provider);
             s_providers->emplace_back(std::move(provider));
 
             if (select || s_providers->size() == 1)
@@ -498,6 +498,10 @@ namespace hex {
             return result;
         }
 
+        void openProvider(std::shared_ptr<prv::Provider> provider) {
+            RequestOpenProvider::post(provider);
+        }
+
     }
 
     namespace ImHexApi::System {

lib/libimhex/source/helpers/patches.cpp

@@ -24,7 +24,7 @@ namespace hex {
             [[nodiscard]] bool isSavable()   const override { return false; }
             [[nodiscard]] bool isSavableAsRecent() const override { return false; }
 
-            [[nodiscard]] bool open() override { return true; }
+            [[nodiscard]] OpenResult open() override { return {}; }
             void close() override { }
 
             void readRaw(u64 offset, void *buffer, size_t size) override {

lib/libimhex/source/providers/cached_provider.cpp

@@ -11,9 +11,9 @@ namespace hex::prv {
         clearCache();
     }
 
-    bool CachedProvider::open() {
+    Provider::OpenResult CachedProvider::open() {
         clearCache();
-        return true;
+        return {};
     }
 
     void CachedProvider::close() {

lib/libimhex/source/providers/memory_provider.cpp

@@ -4,12 +4,12 @@
 
 namespace hex::prv {
 
-    bool MemoryProvider::open() {
+    Provider::OpenResult MemoryProvider::open() {
         if (m_data.empty()) {
             m_data.resize(1);
         }
 
-        return true;
+        return {};
     }
 
     void MemoryProvider::readRaw(u64 offset, void *buffer, size_t size) {